Domestic well reliability: evaluating supply interruptions from groundwater overdraft, estimating costs and managing economic externalities

The effects of groundwater depletion may impose costs on many people that rely upon the resource. Such costs are not borne entirely by the high-volume pumpers that largely create the problematic conditions. Ideally, sustainable groundwater management should include addressing economic externalities and social equity, although information quantifying these concerns is often unavailable. This work estimates impacts to domestic water well owners from groundwater overdraft caused mostly by pumping deeper agricultural wells. A study is presented for Tulare County in the southern Central Valley of California, USA, where many interruptions in domestic well supplies occurred during a recent drought. The case has unusually well-documented conditions and data available for analysis. A method is developed to model supply interruptions and estimate costs for maintaining domestic water well supplies that are impacted by declining groundwater levels. The analysis is performed in the context of planning for sustainable groundwater management and suggestions for managing the economic externality are made. This work may provide a basis for evaluating the economic impacts on well owners from over-pumping in basins outside the study area where less data may be available.